The exploding popularity of health and medical apps is ushering a new wave of sometimes unwelcome visitors into the doctor's surgery. Smartphones and tablets (the screen kind, not the pill kind) have become mobile diagnostic devices.
Fitness apps for monitoring workouts took off first, led by Endomondo, which gives audio feedback on exercise performance, allows friends to follow and barrack live, and claims 10 million users. Zombies, Run! wraps a story around daily exercise, with an eponymous warning if you slow down.
Apps with more specific diagnostic functions are now becoming widely available: mobile devices can monitor your heart rate, log your blood sugars, test your eyes, read your X-rays or scan your moles then despatch the results over the phone to your health practitioner.
The worldwide market for health and medical apps will reach US$1.3 billion this year, having almost doubled since last year, with 247 million downloaded, according to the US market research firm research2guidance. The firm, which specialises in the field becoming known as mHealth, estimates there are 13,000 such apps pitched at consumers and another 5000 aimed at the medical profession.
Doctors are using apps to get the latest information about drugs and treatments, says Ronald McCoy, a spokesman for the Royal Australian College of General Practitioners.
"It used to take a long time [to get new information], but now it gets updated overnight on your phone," he said. This "puts doctors in a better situation to help their patients".
The president of the Australian Medical Association, Dr Steve Hambleton, recently accessed "15 smartphone apps to improve your practice" from a US website. He said one called My Pain Diary might help in understanding and diagnosing patients' experiences of pain.
The Surry Hills GP Jennifer Hunter said she occasionally recommends apps to patients and encourages them to seek out apps for themselves, mostly to help them track their diet and exercise.
The British Department of Health was taken aback when a competition to find the best health apps yielded thousands of responses last year. The Health Secretary, Andrew Lansley, released a list of the top 500 apps to be recommended for doctors to "prescribe" for free as a way of increasing patient power and reducing doctor visits.
In the latest issue of Scientific American, the director of the US National Institutes of Health, Dr Francis Collins, wrote about participating in a trial that allowed him to pick up his iPhone, fire up an app to monitor his heart rate and rhythm, and then beam his ECG reading to a cardiologist halfway around the globe. Mobile devices "offer remarkably attractive low-cost, real-time ways to assess disease, movement, images, behaviour, social interactions, environmental toxins, metabolites and a host of other physiological variables", Collins wrote, prosyletising on their huge potential for medical research and health care.
A spokeswoman for the federal Department of Health said mobile phone applications were a valuable tool to promote public health messages. The department has one providing information about illegal drugs, another one called Swap It encouraging a healthier diet and lifestyle, and MyQuitBuddy to help quit smoking, with a panic button for distraction when the craving hits. More were on the way, she said.
But in the same way he has warned patients against self-diagnosis using internet research, Hambleton urged people to discuss their apps with their doctors. McCoy said it was a case of "buyer beware". "The health industry in general has a lot of products that make outrageous health claims and apps are no different from that."